Interfaces in solid-state batteries and solid oxide fuel cells
Professor Jürgen Janek, University of Giessen, Germany
The thermodynamics and kinetics of solid/solid interfaces are critical for the function of solid-state devices. In this presentation, the current status of research on interfaces in solid-state batteries will be briefly reviewed and compared to the current understanding of interfaces in solid oxide fuel cells. Recently, solid-state batteries are considered as a potential next generation energy storage [1-3], competing with conventional lithium ion batteries. Interestingly, major hurdles on the way to commercialisation have still to be overcome, and the kinetics of interfaces needs to be improved. In particular, the lithium metal anode is a key issue, as it is also the cathode interface where oxidation of solid electrolytes may take place. It is interesting to compare the development of solid-state batteries, which has only started a few years ago, with the development of solid oxide fuel cells. On the route to commercial products, the electrode interfaces and the design of stable electrodes, that offer low impedance kinetics was also a key step towards success, in addition to the development of superior solid electrolytes. Professor Janek’s results will be presented, highlighting the current status of lithium solid electrolytes with high conductivity, the role of interface coatings and natural interphases, as well as the influence of chemo-mechanics on the properties of full battery cells.
1. J Janek and WG Zeier, Nat Energy 1 (2016) 16141
2. Y Kato, S Hori, T Saito, K Suzuki, M Hirayama, A Mitsui, M Yonemura, H Iba, and R Kanno,
Nat Energy 1 (2016) 16030
3. Y J Nam, D Y Oh, S H Jung, and Y S Jung, J Power Sources 375 (2018) 93
Nanoscale effects and interfaces in lithium batteries
Professor Linda Nazar, University of Waterloo, Canada
While it is widely acknowledged that traditional Li-ion batteries, which work on the principle of reversible storage of electrons and Li-ions in bulk materials, are approaching their limits, the question is: what real opportunities lie beyond? This presentation will focus on the challenge to find better electrochemical energy storage systems that go “beyond Li-ion” batteries. Topics will encompass multivalent intercalation batteries, solid-state batteries, and cells that operate on the basis of “conversion” chemistry rather than conventional intercalation chemistry. These represent new technologies that could meet the needs for high energy density and/or high power storage, yet many barriers remain to realising their full promise. They require cleverly designed nanomaterials for the electrodes, different electrolyte strategies than those used for Li-ion batteries and advanced electrode architectures based on nanostructured design. Guiding materials development also requires developing a fundamental understanding of the underlying chemistry of redox processes, which will be a focus of this lecture.
Nanostructures and interfaces of solid oxide fuel cell materials
Professor John Irvine, University of St Andrews, UK
Lithionics: store energy, compute data and chemically sense environment based on lithium
Professor Jennifer Rupp, Massachusetts Institute of Technology, USA
Next generation of energy storage and sensors may largely benefit from fast Li+ ceramic electrolyte conductors to allow for safe and efficient batteries and real-time monitoring anthropogenic CO2. Recently, Li-solid state conductors based on Li-garnet structures received attention due to their fast transfer properties and safe operation over a wide temperature range. Through this presentation basic theory and history of Li-garnets will first be introduced and critically reflected towards new device opportunities demonstrating that these electrolytes may be the start of an era to not only store energy or sense the environment, but also to emulate data and information based on simple electrochemistry device architecture twists. The first part of the presentation focuses on the fundamental investigation of the electro-chemo-mechanic characteristics and design of disordered to crystallizing Li-garnet structure types and their description. Understanding the fundamental transport in solid state is discussed, asking the provocative question: how do Li-amorphous to crystalline structures conduct? How we can alter their charge and mass transport properties for solid electrolytes and towards electrodes is discussed. Here, the researcher firstly presents new Li-garnet battery architectures for which we discuss lithium titanate and antimony electrodes in their making, electrochemistry and assembly to full battery architectures. Secondly, new insights on degree of glassy to crystalline Li-garnet thin films are presented based on model experiments of the structure types. Here, the thermodynamic stability range of maximum Li-conduction, phase, nucleation and growth of nanostructure is discussed using high resolution TEM studies, near order Raman investigations on the Li-bands and electrochemical transport measurements. The insights provide novel aspects of material structure designs for both the Li-garnet structures (bulk to films) and their interfaces to electrodes, which we either functionalise to store energy for next generation solid state batteries or make new applications such as Li-operated CO2 sensor tracker chips. In the final part the presentation reviews in a more holistic picture how one can use such materials and change the electrochemistry from energy storage, chemical sensing to data emulation for which we see prospect for electric vehicles, the Internet of Things or hardware in artificial intelligence.